This invention is directed to a locking lance tab preassembly attachment system for a box-section frame member, and more particularly, to a lance tab and complementary recess which is preferably a temporary connection between two channel members which are pre-assembled, transported and then welded together permanently to form a box-section frame member.
This invention is an improvement of the subject matter of Felt U.S. Pat. No. 3,420,032. In the Felt Patent, the lance and hole sizes are designed for a suitable clearance in all directions so that the assembly locks together loosely. This feature allowed the welding fixtures to shift and hold the parts in correct (or compensated) dimensional relationship in any of a plurality of welding fixtures for final welding.